Many industries are engaged in the manufacture of metal components. These components are manufactured with a variety of processes such as stamping, drawing, grinding, broaching and cutting.
After the metal component is manufactured, it is cleaned prior to painting or further processing. Some of the cleaning is performed with water based compounds where the compound is sprayed onto the part, or the part is soaked at elevated temperature with agitation, and the part rinsed. These methods are used when the part does not have to be scrupulously clean. When absolutely no foreign matter may be left on the parts, degreasing machines have been used. These machines usually employ chlorinated hydrocarbon solvents. The materials removed, e.g., oils and other compounds on the part, however, accumulate in the solvent.
Metal parts typically are cleaned by a multi-step batch operation. Parts to be cleaned are degreased to remove oil and organic contaminants, either by exposing them to trichloroethylene vapor or by immersing them in a tank of caustic solution. The degreased parts are rinsed in a second tank, subjected to a descaling or an oxide-removal acid pickle treatment in a third tank, and rinsed in a fourth tank. These tanks occupy considerable floor space, thereby increasing the cost of the cleaning process. This cleaning operation also requires maintaining the strength and concentration of the treating baths. Further, where high-carbon steel, or inadequately degreased parts are pickled, the organic pickling acids often leave a carbon smut on the metal surface. In addition, acid pickling tends to cause hydrogen embrittlement. In addition, the compositions employed tend to have high concentrations of acids can cause excessive attack of metals such as copper.
Although the methods and compositions of the art have been useful for cleaning metals, those methods and compositions are expensive, cumbersome, tend to cause hydrogen embrittlement as well as to corrode excessive mounts of the underlying base metal. A need therefore exists for compositions and methods which avoid the disadvantages of the art.